There is known a projection type display apparatus that projects an image on a screen. In most of such projection type display apparatuses, a liquid crystal panel (liquid crystal light shutter) is used for forming the image.
Such a liquid crystal panel has a configuration in which, for example, an opposed substrate for a liquid crystal panel that is provided with a black matrix, a common electrode and the like is joined to a liquid crystal driving substrate provided with a large number of thin film transistors (TFT) for controlling respective pixels and a large number of pixel electrodes via a liquid crystal layer.
In the liquid crystal panel (TFT liquid crystal panel) having such a configuration, since the black matrix is formed in a portion other than the portions to become the pixels in the opposed substrate for a liquid crystal panel, a region for light transmitting the liquid crystal panel is restricted. This makes light transmittance be lowered.
In order to improve the light transmittance for the liquid crystal panel, there is known a liquid crystal panel in which a large number of minute microlenses are provided at the positions corresponding to the respective pixels in the opposed substrate for a liquid crystal panel. According to such a liquid crystal panel, light transmitting an opposed substrate for a liquid crystal panel is condensed into openings formed in a black matrix, and this makes it possible to improve light transmittance.
As a method of forming such microlenses, for example, a method in which an uncured photocuring resin material is supplied on a substrate with concave portions on one major surface of which a plurality of concave portions for forming microlenses are formed, a flat transparent substrate (cover glass) is joined to the supplied resin material to press and bring into contact with the supplied resin material, and the supplied resin material is then cured, that is, a so-called 2P method is known (for example, see JP-A-2001-92365).
However, since an uncured resin material is used to manufacture a microlens substrate, it has been difficult to obtain a microlens substrate having sufficient durability in the case of using such a method. In particular, since deterioration or the like of the resin material tends to be generated due to light having a small wavelength in a photocuring resin material used in the 2P method, there is a possibility that sufficient light resistance of a manufactured microlens substrate cannot be obtained. In addition, since a microlens substrate is manufactured using three members including a resin layer formed of a photocuring resin material, a cover glass, and a substrate with concave portions, strain or the like tends to be generated due to difference in coefficients of thermal expansion thereof, and as a result, there is a possibility that characteristics of the microlens substrate such as an optical characteristic are lowered. For example, a step of aligning the cover glass or the like is required in such a method, and therefore, the manufacturing process has been complicated. Further, in the case where the cover glass is polished in order to obtain an optimal optical path length, stains and the like occur due to the polish process. Thus, although an appropriate cleaning process is required, there is a possibility that such a cleaning process results in deterioration or the like of the resin material constituting the resin layer. As a result, there is a possibility that the quality of the manufactured microlens substrate is lowered and this results in lowering of a yield rate of manufacturing the microlens substrates.